Gas turbine engines, of the type typically used in aircraft applications, include, in serial flow communication, a fan section, through which ambient air is drawn into the engine, a multistage compressor for pressurizing the incoming air, a combustion section, in which the high pressure air is mixed with atomized fuel and ignited, and a turbine section that extracts the energy from hot gas effluent to drive the compressor and fan, producing desired engine thrust. An augmentor is used primarily to provide extra thrust for relatively short periods of time, which may be required during e.g., takeoff and high speed maneuvers, and can also be included to increase the thrust generated by engine. To achieve this, the augmentor injects additional fuel into the exhaust gases exiting the turbine of the engine.
Accordingly, gas turbine engines include at least one internal fuel delivery manifold that is mounted inside or outside the engine casing to distribute fuel to both the main combustors of the engine and to the thrust augmentor section. A conventional fuel manifold system is typically formed as an annular ring so that it can be positioned outside the high temperature environment of the combustion areas, having at least one fuel inlet, and including a plurality of outlet connections configured to feed an array of nozzles, carburetors, fuel valves and/or spray bars and/or rings that extend into the combustion areas. Typically, fuel manifolds include more than one fuel conduit or tubes for feeding different nozzle systems, or for accommodating fuels at different pressure or flow rates. Fuel recirculation conduits, drains or cooling conduits can also be included within the annular fuel manifold configuration, as is well known in the art. The resulting multi-conduit fuel manifold system includes several annularly formed tubes that are nested together or oriented side-by-side relationship and joined together.
As will be appreciated, the more complex the fuel system requirements, the more complex the fuel manifold system construction. For example, where three or more separate fuel conduits are required by the application (to supply additional fuel nozzles, for cooling or for staging), the size and weight of the fuel manifold increases, decreasing overall fuel burning efficiency of the engine.
FIG. 1 illustrates a prior art gas turbine fuel manifold including three separate fuel delivery conduits that are secured together in a spaced apart fashion with mounting brackets. Each conduit includes multiple tubular components formed into a ring and welded or otherwise joined together. As illustrated, each of the assembled rings includes a significant number of joints. Each joint of the manifold requires proof testing and must be leak free and, accordingly, is subject to failure under the extreme operating conditions of the engine.
In light of the foregoing, there exists, therefore, a need in the art for multi zone or multichannel fuel manifolds for gas turbine engines that minimize the number of joints or connections required to form the manifold, thereby minimizing maintenance and minimizing the risk of manifold failure over the engines operating life. In addition, there is a need to reduce the size and weight of multi zone or multichannel to decrease the overall weight of the engine and size of the engine envelope. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.